Laboratory Investigation of PWSCC of CRDM Nozzle 3 and Its J-Groove Weld on the Davis-Besse Reactor Vessel Head

Hongqing Xu and Steve Fyfitch AREVA

Framatome ANP, Inc., P.O. Box 10935, Lynchburg, VA 24506-0935

James W. Hyres BWXT Services, Inc., 2016 Mt. Athos Road, Lynchburg, VA 24504-5447

Abstract In February 2002, significant boric acid corrosion of the Davis-Besse low alloy steel reactor pressure vessel (RPV) closure head was uncovered around control rod drive mechanism (CRDM) nozzle No. 3. Subsequent on-site non-destructive examinations (NDE) found that nozzle No. 3 had developed through-wall cracks due to primary water stress corrosion cracking (PWSCC) next to the J-groove weld. The CRDM nozzle 3 and its J-weld were carefully examined in the laboratory by fluorescent penetrant testing and stereomicroscopy that identified the remnant of the axial cracks in the Alloy 600 nozzle as well as the circumferential and axial cracks in the Alloy 182 J-groove weld. These cracks were subsequently sectioned for light optical metallography (LOM) and scanning electron microscopy (SEM) for characterization. This paper summarizes the results and conclusions of the laboratory investigative efforts on the PWSCC of Alloy 600 CRDM nozzle No. 3 and its Alloy 182 J-groove weld.

E-mail: Hongqing.Xu@framatome-anp.com

I. INTRODUCTION

Davis-Besse Nuclear Power Station in Oak Harbor, Ohio, is a Babcock & Wilcox (B&W) designed 177-FA (fuel assembly) pressurized water reactor (PWR), which went into commercial operation in 1977. Davis-Besse initiated its 13th refueling outage (13RFO) in February 2002 after an accumulated 15.78 effective full power years (EFPYs) of operation. After removal of insulation from the reactor pressure vessel (RPV) head, boric acid crystal deposits and iron oxide were found to have flowed out from several of the openings in the lower service structure support skirt. A schematic diagram of the Davis-Besse RPV head and the J-groove weld is shown in Fig. 1. Subsequent non-destructive examinations (NDE) identified axial cracks in five control rod drive mechanism (CRDM) nozzles adjacent to the J-groove weld. In three CRDM nozzles (Nos. 1, 2, and 3) located near the center of the RPV head, the through-wall axial cracks extended above the J-groove weld. The CRDM nozzles are fabricated from Alloy 600 and attached to the RPV head by an Alloy 182 J-groove weld. Both of these materials are known to be susceptible to

primary water stress corrosion cracking (PWSCC). Similar axial cracks in CRDM nozzles have also been observed in other B&W 177-FA PWRs.1

Initially, it was intended that the five CRDM nozzles would be repaired by boring out the original J-groove weld and the lower part of the nozzle containing the cracks, and re-welding the remaining nozzle back to the RPV head. After boring out the lower part of nozzle 3, a large corrosion cavity was found on the down-hill side of the low alloy steel RPV head. Subsequently, a 17.5-inch (444 mm) diameter disc containing the remaining portion of the nozzle 3 J-groove weld, part of the nozzle 11 J-groove weld, and the entire cavity was sectioned from the RPV head by using water jet cutting. This disc, along with the remnants of nozzles 2 and 3, were shipped to the laboratory for further examinations. This paper focuses on the nozzle 3 and the J-groove weld examinations. The other two companion papers in the proceedings2,3 describe the examination results of the RPV head low alloy steel boric acid corrosion and the cracking identified in the exposed stainless steel cladding.

Proceedings of the 12th International Conference onEnvironmental Degradation of Materials in Nuclear Power System Water Reactors

Edited by T.R. Allen, P.J. King, and L. Nelson TMS (The Minerals, Metals & Materials Society), 2005

833

Close-up of the J-groove weld

Nozzle 3 is near the center of RPV head CRDM leadscrew

assembly

Alloy 600 nozzle

Low alloy steel, SA-533, Gr. B, Cl. 1, plate

Type 308 stainless steel cladding

Alloy 182 buttering and J-groove weld

180o

0o Nozzle removal height

Fig. 1. Schematic of Davis-Besse RPV head and close-up of the J-groove weld.

II. ALLOY 600 CRDM NOZZLE MATERIAL AND J-GROOVE WELD FABRICATION

The CRDM nozzles were fabricated from Alloy 600 seamless tubing per ASME SB-1674. CRDM nozzles 1 to 5 were fabricated from Heat M3935, which was supplied by the B&W Tubular Products Division (B&W TPD). Currently, there have been more leaking CRDM nozzles from Heat M3935 than from any other single heat used in the B&W 177-FA PWRs. The final mill anneal temperature is estimated at 1600-1700F (871-927C). The chemical composition and mechanical properties from the certified material test report (CMTR) for Heat M3935 are listed in Table I. The rough and final nozzle machining took place after the final mill anneal. The final dimensions of the CRDM nozzles are approximately 4.00 inches (102 mm) outside diameter (O.D.) with 0.625 inch (15.9 mm) wall thickness. The CRDM penetrations were machined in the RPV head, which had already been cladded with ~3/16 inch (4.76 mm) of Type 308 stainless steel (see Fig. 1). The J-groove weld preparations were ground into the inside diameter (I.D.) of the RPV head. After grinding, the J-groove weld preparations were buttered with Alloy 182 (E-NiCrFe-3) to the SA-533 Gr. B low alloy steel using the manual metal arc welding process. After the buttering, the RPV head was stress relieved at 1125 +/- 40F (800 +/- 22C) for 8 hours. Each nozzle was custom ground for a diametrical interference fit of 0.0010 to 0.0021 inch (0.025 to 0.053

mm) with the CRDM penetrations in the RPV head. Each Alloy 600 nozzle was then attached to the buttering by a partial penetration weld (J-groove weld) with Alloy 182 filler material. No post weld stress relief was performed after the J-groove weld. During plant operation, the temperature near the CRDM nozzle J-groove weld locations is estimated to be 605F (318C).

Table I.

CRDM Nozzle 3, Heat M3935 CMTR Report

C Mn Fe S Si P Cu Ni Cr Co

0.028 0.27 6.25 0.0022 0.37 0.0040 0.01 77.89 15.58 0.010

Yield Strength Tensile Strength Elongation

48.5 ksi (334 MPa) 85.6 ksi (590 MPa) 60%

III. LABORATORY EXAMINATIONS OF ALLOY 600 CRDM NOZZLE 3

III. A. PT Examination and Sectioning

On-site NDE examinations detected 4 axial cracks in nozzle 3 near the J-groove weld as indicated in Fig. 2. No NDE had been performed to identify any cracking in the CRDM nozzle J-groove weld. Because nozzle 3 was bored from below to a height slightly above the J-groove weld at

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the up-hill side, most of the axial cracks in the nozzle were known to be lost, except maybe a portion of the #3 axial crack on the up-hill side (180). A 1-inch (25.4 mm) long ring was sectioned off the lower end of the as-received nozzle 3. The fluorescent dye penetrant test (PT) performed in the laboratory revealed a cluster of partial through-wall axial crack indications near the 180 location. These axial cracks initiated from the nozzle I.D. surface with the deepest crack extending up axially ~0.5 inch (12.7 mm) from the end face and radially ~0.125 inch (3.2 mm) into the nozzle wall from the I.D. surface, consistent with the on-site NDE results. In addition, the on-site NDE results indicated that the through-wall portion of the #3 crack extended ~0.5 inch (12.3 mm) above the J-groove weld on the nozzle 3 O.D., corresponding approximately to the nozzle removal height. However, there were no signs of boric acid corrosion on the nozzle 3 penetration I.D surface at the up-hill side (180). Hence, the boric acid leakage on the up-hill side of nozzle 3 could not be positively confirmed by the destructive examinations in the laboratory. After the PT examination, the cracked area on the ring (near 180) was sectioned transversely as shown in Fig. 3. After cutting away most of the crack-free portion near the O.D in the specimen C1A, the main axial crack was opened for scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS). The specimen C1B was mounted for light optical metallography (LOM) and microhardness measurements. The specimen C1C, containing the main axial crack tip, is planned to be sent to a second laboratory for additional work using analytical transmission electron microscopy (ATEM)5.

III. B. Fractography, Metallography, and Hardness Test

The partial through-wall axial crack in the specimen "C1A", was opened for SEM examination. Fig. 4 shows that the in-service fracture surface is exclusively intergranular. The ductile dimple tearing fracture surface at the top edge is the ligament broken in the laboratory. The higher magnification photos in Figure 4 show a typical "rock candy" surface due to intergranular stress corrosion cracking (IGSCC). In addition, secondary crack branching, often associated with IGSCC, is also visible. Fig. 5 is a micrograph near the nozzle 3 I.D. surface. The intergranular cracking is extremely tight near the I.D. surface where the IGSCC initiated. The machined I.D. surface showed no discernable cold work. Fig. 6 shows a representative micrograph of the nozzle 3 microstructure. It shows the grain boundaries decorated with fine globular semi-continuous carbides. Compared to similar mill annealed Alloy 600 tubing and bar, the microstructure shows far fewer intragranular carbides. This could be partly due to the low carbon content of this heat (see Table I). On the other hand, Figs. 5 and 6 show a number of titanium or niobium carbonitrides [Ti(CN) or Nb(CN)],

which are identified by their angular shapes and distinct yellow-to-orange color. These particles are often present in nickel-based alloys such as Alloy 600. Even though Alloy 600 does not specify Ti and Nb, some trace amount is always present. The average grain size of the nozzle 3 material was determined to be ASTM No. 3.0 using the Abrams three-circle procedure per ASTM E 112-966. A microhardness traverse was performed across the nozzle 3 wall thickness (Fig. 7). The Knoop 500 gram microhardness varies from 179 to 221, which is equivalent to HRB 85 to 94. The slight variation and general hardness level is consistent with the mill annealed Alloy 600 tubing materials.

26

27

28

29

30

0o 90o 180o 270o 360o

Inche

s fro

m CR

DM F

lange

J-Groove WeldContour

#1

#2#3

#4

Fig. 2. On-site NDE of nozzle 3 showed 4 axial cracks. #1 and #3 were through-wall, #2 and #4 were partially through-wall.

180o

270o 90o

0o

170o 180o 190o

Met mount surface

C1A

C1B

C1C

Fig. 3. Sectioning of the nozzle 3 ring. Left: viewing the lower face of the as-removed nozzle 3. Right: the side view (viewing the I.D. surface) of sectioning ~180. The axial crack in the specimen C1A was opened for SEM. The specimen C1B was mounted for metallography.

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Secondary IGSCCbranching

Fig. 4. Top, SEM of the axial crack surface of the specimen "C1A" (~180o, nozzle 3). Magnifications, top 13X, middle 68X, and bottom 46X. Middle and bottom are close-ups of the two boxed areas. The in-service crack surface has a "rock candy" appearance due to IGSCC. Secondary IGSCC cracks are also visible. The dimpled fracture surface was made in the laboratory.

Fig. 5. Mag. 75X, phosphoric-nital dual etch. IGSCC in specimen C1B. The edge at right is the nozzle 3 I.D.

Fig. 6. Mag. 281X, etched with phosphoric acid. Typical microstructure of nozzle 3. The grain boundaries were decorated with fine semi-continuous carbides, but few intragranular carbides. The large particles are Ti, Nb (CN).

150

170

190

210

230

250

0.00 0.10 0.20 0.30 0.40 0.50

Distance from CRDM Nozzle I.D. surface, inches

Kno

op 5

00 g

ram

Fig. 7. Microhardness varies from 179 to 221, equivalent to HRB 85 to 94, across the nozzle 3 wall thickness.

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IV. LABORATORY EXAMINATIONS OF ALLOY 182 J-GROOVE WELD

IV. A. PT Examination and Sectioning

The approximately 8-inch thick, 17.5-inch diameter disc was sectioned into two halves. Fig. 8 shows the lower half of the corrosion cavity and the initial cuts made to harvest the crack specimens. Before sectioning, fluorescent PT was performed on the entire underside of the cavity and the I.D. surface of the J-groove weld bore. On the bottom surface, or the reactor coolant system (RCS) side, the PT revealed a cluster of short discontinuous circumferential cracks on the J-groove weld surface between 0 and 45 (see Fig. 9). These cracks are located at 0.75 inch (19 mm) radially from the penetration bore I.D. The boundary between the Alloy 182 J-groove weld and the stainless steel cladding on the bottom surface is about 1.1 inches (28 mm) radially from the bore I.D. The specimen sectioning orientation for examining the circumferential cracks is illustrated in Fig. 9. The PT also identified one axial crack on the down-hill side (~10) of the bore I.D. surface. This crack is about ~1.4 inches (36 mm) long, extending to the top surface of the exposed J-groove weld and was facing directly toward the nose of the corrosion cavity. This crack appears to be an extension of the #1 through-wall crack identified by the on-site NDE (see Fig. 2). Close examination of the J-groove weld bore I.D. surface with a stereo microscope revealed two additional axial cracks near the up-hill side (~180, see Fig. 10). The three specimens containing the axial cracks at ~10 and 180 are illustrated in Fig. 10 and Fig. 11. The examination results are described below.

270o

180o 0o

90o

Exposed Alloy 182 J-groove weld Exposed stainless

steel cladding

Low alloy steelcavity side wall

Fig. 8. Top view of the sectioned corrosion cavity. The corrosion was due to boric acid leakage from the through-J groove weld-wall axial crack (at ~10) in Alloy 600 nozzle 3 above the J-groove weld and in the J-groove weld itself.

Circumferential indicationsare in the J-groove weldbetween 0o and 45o and0.75 inch from the bore I.D.

Specimen A2A6A2B2mounting plane

Fig. 9. The bottom surface (RCS side) of the cavity piece shown in Fig. 8. The PT examination was performed before the sectioning. The mounting surface orientation for the specimen A2A6A2B2 is indicated.

Top of theexposed J-groove weld

270o

180o

0o

Sectioning forSpecimen A2A2B3

Sectioning forspecimensA2A6B2 & -B3

Fig. 10. Two tight axial cracks on the bore I.D. surface at ~180o (indicated by the two black arrows). The sectioning locations of specimens "A2A2B2" and "A2A6B3" are illustrated. The transverse mounting faces are indicated by the solid lines.

Axial crack in"A2A6B3" opened forfractography

"A2A6B2", lower face mounted

Fig. 11. Sectioning detail for the specimens "A2A6B2" "A2A6B3". Axial crack in the J-groove weld at ~10.

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IV. B. Axial Cracks at Up-Hill Side (~180)

The mounted A2A2B3 specimen in Fig. 12 was transversely sectioned from the J-groove weld at ~180 (also see Fig. 10). Three axial cracks are visible in Fig. 12, with the deepest crack (~180) about 0.236 inch (6.0 mm) below the I.D. surface. None of the axial cracks at ~180 had penetrated the J-groove weld thickness. A microhardness traverse across the J-groove weld is also shown in Fig. 12. The elevated hardness level near the I.D. surface was due to a cold worked layer from the nozzle removal operation. In the middle of the J-groove weld, the Knoop 500 gram microhardness varies from 220 to 268, higher than the CRDM nozzle 3 (see Fig. 7). Fig. 13 is a composite macrograph of the center crack in Fig. 12. The higher magnification micrographs showed cracking was interdendritic, consistent with PWSCC in Alloy 182 welds in PWRs. Such interdendritic cracking in the weld is referred to as IDSCC, the equivalent of IGSCC in Alloy 600. Compared to the tight IGSCC in the Alloy 600 nozzle (Fig. 5), the main IDSCC crack path is wider. The corrosion in the dendrite boundaries was more severe than the corrosion in the grain boundaries. This may be due to a higher level of, or wider segregation of low melting impurity elements along the dendrite boundaries in the weld compared to the grain boundaries in the wrought materials.

Bore I.D.

180o

Microhardnesstraverse line

175o 185o

210

230

250

270

290

310

0.00 0.10 0.20 0.30 0.40 0.50

Distance from bore I.D. surface, inches

HK

500

gra

m

Fig. 12. Top, Mag 5X. Specimen A2A2B3. Three axial cracks are visible at ~175, 180, and 185. The deepest crack in the center is about 0.236 inch below the I.D. of the bore. Bottom, Knoop microhardness across the J-groove weld.

The bore I.D.

Fig. 13. Magnifications: 13X (top), 75X (middle), and 280X (bottom). The axial crack at ~180 shown in Fig. 12.

IV. C. Axial Cracks at Down-Hill Side (~10)

Fig. 14 is a composite macrograph of the mounted specimen A2A6B2 containing the axial crack at ~10. The specimen was transversely sectioned from the J-groove weld at ~10 (see Fig. 10 and Fig. 11). The higher magnification micrographs are shown in Fig. 14. The interdendritic cracking morphology is similar to the axial cracks at ~180, except the main crack path is even wider (note the different magnifications for Fig. 13 and Fig. 14). The wide crack opening near the exposed J-groove weld surface facing the cavity may be partly attributable to the flow of leaking primary coolant. The J-groove weld microstructure at ~10is similar to that at ~180. The specimen "A2A6B3" was also sectioned from the J-groove weld at ~10, but directly below the specimen "A2A6B2" (see Figs. 10 and 11). Fig. 15 shows a composite SEM macrograph of the opened crack surface in the specimen A2A6B3. The higher magnification SEM micrograph in Fig. 16 shows that the interdendritic in-service cracking surface clearly delineated a columnar weld

838

solidification structure. The center part of the fracture surface was coated with a thick corrosion layer. Comparing Figures 14 and 15, the center fracture surface covered by the thick corrosion layer corresponds to pockets of cavities along the crack path near the exposed surface. The pockets were probably formed when the dendrites were encircled by cracks and removed by the leaking coolant.

Exposed J-groove weld surface

The bore I.D.

Fig. 14. Magnifications: 4.3X (top), 75X (middle), and 280X (bottom). Specimen A2A6B2: the axial cracks in the J-groove weld at ~10. The cracks are much wider than the axial crack seen in the J-groove weld at ~180 (see Fig. 13).

The bore I.D. Exposed J-groove weld surface

Interdendritic crackingCovered by corrosion product

Ductiletearing

Fig. 15. Mag. 4.3X. SEM of the opened crack near ~10 in the specimen A2A6B3. The ductile tearing fracture surface was made in the laboratory.

Fig. 16. Mag. 10X. Interdendritic cracking of the in-service fracture surface shown in Fig. 15.

IV. D. Circumferential Cracks at Bottom Surface

Fig. 17 shows the mounted metallographic specimen A2A6A2B2 containing the circumferential cracks on the J-groove weld bottom surface. The mounting plane of the specimen A2A6A2B2, illustrated in Fig. 9, is parallel to the nozzle axis and perpendicular to the nozzle circumference at ~45. Fig. 18 shows that these circumferential cracks are interdendritic and propagated along the columnar solidification structure, similar to the axial cracks in the J-groove weld. Specimen A2A6A2D2 was sectioned from the J-groove weld at ~30 and mounted in a similar orientation as the specimen A2A6A2B2. Both specimens showed similar circumferential cracks. These circumferential cracks were very shallow, penetrating approximately 0.020 inch (0.51 mm) or less below the surface. Additional examinations determined that these circumferential cracks, initiated on the Alloy 182 J-groove weld bottom surface, were not connected to the axial cracks in the J-groove weld, which initiated on the Alloy 600 CRDM nozzle 3 I.D. surface.

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A portion of the circumferential crack at ~20 was sectioned off and bent slightly to open the cracks for SEM. The SEM micrograph in Fig. 19 (top) shows numerous shallow cracks on the bottom surface of the J-groove weld. A close-up in Fig. 19 (bottom) clearly reveals the interdendritic nature of the in-service circumferential crack surface.

Corrosion cavity in RPV head

Interdendriticcracks, seeFig. 20.

Boric acidattack, seeFig. 21.

RCS side

see Fig. 18

Fig. 17. Mag. 6.7X. Specimen A2A6A2B2. The J-groove weld at ~45. The circumferential cracks were initiated on the bottom surface of the J-groove weld. The corrosion cavity, at the upper left corner of this figure, was due to removal of low alloy steel by boric acid corrosion. The exposed stainless steel cladding and J-groove weld surface was attacked by oxygenated and concentrated boric acid.

Fig. 18. Mag. 87X. Close-up of the shallow circumferential cracks on the bottom surface of the J-groove weld shown in Fig. 17.

Fig. 19. Magnifications, top 10X, bottom 135X. Top, circumferential cracks at ~20. The specimen was bent slightly to open the cracks. Bottom, high magnification of a crack opening shows the interdendritic cracking surface.

IV. E. Surfaces Exposed to the Oxygenated Boric Acid in the Corrosion Cavity

In addition to the circumferential cracking on the bottom surface of the J-groove weld, interdendritic cracking initiating from the exposed stainless steel cladding surface was observed in the specimen A2A6A2B2 shown in Fig. 17. These cracks appear to be due to corrosive attack on the exposed cladding surface from the oxygenated and concentrated boric acid slurry inside the cavity. The tips of two cracks extended into the Alloy 182 J-groove weld as shown in Fig. 20. In the stainless steel cladding, the cracks were perpendicular to the exposed cladding surface and along the solidification direction. However, the cracks preferentially followed the elongated delta ferrite pools, which were preferentially attacked relative to the austenitic matrix. After extending into the Alloy 182 J-groove weld,

840

the crack changed direction to propagate along the J-groove weld columnar solidification structure. The exposed J-groove weld surface was also attacked by the oxygenated and concentrated boric acid in the corrosion cavity (see Fig. 21); however, unlike in the stainless steel cladding, none of these attacks were very deep.

RPV headcorrosion cavity

Alloy 182J-grooveweld

Type 308stainlesssteelcladding

Fig. 20. Micrograph of the interdendritic cracks initiated from the exposed cladding surface and extending into the J-groove weld (the boxed area in Fig. 17). Mag. 28X.

RPV headcorrosion cavity

Alloy 182J-grooveweld

Fig. 21. Mag. 75X. Specimen A2A6A2D2. Shallow interdendritic cracks on the exposed J-groove weld surface due to attack by the boric acid slurry in the cavity.

V. DISCUSSION

A cluster of shallow axial cracks was identified at the up-hill side (~180) in the remnant of the Alloy 600 CRDM nozzle 3 by PT performed in the laboratory. The deepest partially through-wall crack is consistent with the on-site NDE results on nozzle 3. The intergranular cracking is consistent with Alloy 600 PWSCC in PWRs. The phenomenon of shallow cracks initiating in a cluster (also called craze cracking) on the CRDM nozzle I.D. surface near the J-groove weld has been observed previously in other B&W 177-FA plants1. Metallography shows a machined nozzle 3 I.D. surface without signs of discernable cold work. The Alloy 600 nozzle microstructure shows the grain boundaries decorated with fine globular semi-continuous carbides. The microstructure also contains very few intragranular carbides. The hardness of HRB 85-94 across the nozzle cross section is typical for a mill annealed Alloy 600 material. These microstructural characteristics are considered favorable for Alloy 600 PWSCC resistance. However, this heat also has a very large grain size of ASTM No. 3, which is considered undesirable for PWSCC resistance. In the Alloy 182 J-groove weld, three axial cracks were identified on the bore (or penetration) I.D. surface at the up-hill side (~180). Optical metallography shows these interdendritic cracks to be consistent with Alloy 182/82 IDSCC in PWRs. None of these axial cracks penetrated through the J-groove weld. No signs of boric acid corrosion to the low alloy steel RPV head penetration were observed on the up-hill side, even though the on-site NDE results indicated that a portion of the #3 crack in nozzle 3 was through-wall above the J-groove weld. On the down-hill side of the J-groove weld, the axial crack at ~10o extended to the top surface of the exposed J-groove weld and was facing directly toward the nose of the corrosion cavity. This crack was likely an extension of the #1 through-wall crack in nozzle 3 identified by the on-site NDE. The interdendritic cracking morphology is similar to the axial cracks at the up-hill side. Compared to the IGSCC cracks in the CRDM nozzle, the main IDSCC crack path is seen to be much wider. Welds microstructures have a higher level of segregation of low melting impurity elements along the dendrite boundary. The dendrites are also smaller than the grains in the wrought Alloy 600. The small dendrites encircled by IDSCC cracks along the main crack path are much easier to remove with crack propagation. It can be inferred that the primary coolant leak rate would be anticipated to be higher through weld IDSCC cracks than through IGSCC cracks in the nozzle. It is postulated that, once the crack breached the J-groove weld, the leak rate would have significantly increased. The shallow circumferential cracks at the J-groove weld bottom surface (exposed to the RCS water) between 0 and 45 are IDSCC, similar to the axial cracks in the J-groove weld. Interestingly, these circumferential cracks in the J-

841

groove weld also initiated in a cluster. The Alloy 182 J-groove weld had long been considered more resistant to PWSCC than the Alloy 600 CRDM nozzles. However in recent years, an increase in PWSCC incidents in Alloy 182 welds has been observed7. In one B&W 177-FA plant, some axial cracks in the CRDM nozzles below the J-groove weld seemed to have initiated in the J-groove weld1. However, for nozzle 3, the circumferential cracks initiated on the bottom surface of the J-groove weld were shallow and not connected to the axial cracks in the J-groove weld. Hence, the axial cracks in the CRDM nozzle 3 and J-groove weld must have initiated on the Alloy 600 nozzle I.D. surface due to PWSCC. The exposed J-groove weld and stainless steel cladding surface was attacked by the oxygenated and concentrated boric acid slurry in the corrosion cavity. The tips of several cracks initiated on the cladding surface extended into the Alloy 182 J-groove weld.

VI. CONCLUSIONS

1. The axial cracks found in the CRDM nozzle 3 and in the J-groove weld are consistent with the on-site NDE results and are typical of PWSCC. The axial cracks initiated at the CRDM nozzle I.D. surface and propagated into the J-groove weld at the up-hill and down-hill locations.

2. At the up-hill side (~180), the portion of the through-wall crack above the J-groove weld identified by the on-site NDE was lost during the nozzle removal process. The axial cracks in the J-groove weld were only partially through-wall. However, there was no sign of any boric acid leakage near the up-hill side to confirm any of the up-hill cracks were through-wall.

3. At the down-hill side (~10), the axial crack was through-wall in both the nozzle above the J-groove weld and the J-groove weld itself. This crack was the primary source of the leaking boric acid, which caused the large corrosion cavity seen on the low alloy steel RPV head. The crack path was wider in the Alloy 182 J-groove weld than in the Alloy 600 nozzle. It is postulated that the boric acid leak rate significantly increased after the axial crack breached the J-groove weld at the down-hill side.

4. A cluster of circumferential PWSCC cracks initiated on the J-groove weld bottom surface exposed to the RCS water. These circumferential cracks were very shallow and were not connected to the axial cracks in the J-groove weld.

5. Shallow interdendritic cracks were also found on the exposed Alloy 182 J-groove weld surface due to corrosion attack from the oxygenated and concentrated boric acid slurry inside the cavity at elevated temperatures.

REFERENCES

1. M.R. Robinson, D.E. Whitaker, M.L. Arey, and S. Fyfitch, Recent CRDM Nozzle PWSCC Experience at Oconee Nuclear Station, Fontevraud 5, Proceedings of Contribution of Materials Investigation to the Resolution of Problems Encountered in Pressurized Water Reactors, September 23-27, 2002, SFEN, Paris, France (2002).

2. H. Xu and S. Fyfitch, and J.W. Hyres, Laboratory Investigation of the Stainless Steel Cladding on the Davis-Besse Reactor Vessel Head, the 12th International Conference on Environmental Degradation of Materials in Nuclear Power Systems Water Reactors. TMS, Salt Lake City, Utah (2005).

3. H. Xu and S. Fyfitch, and J.W. Hyres, Boric Acid Corrosion of the Davis-Besse Reactor Pressure Vessel Head, the 12th International Conference on Environmental Degradation of Materials in Nuclear Power Systems Water Reactors, TMS, Salt Lake City, Utah (2005).

4. Specification for Nickel-Chromium-Iron Alloy Seamless Pipe and Tube, American Society of Mechanical Engineers Boiler and Pressure Vessel Code Section II, Part B, SB-167, ASME, New York, NY (1965).

5. L.E. Thomas, V.Y. Gertsman, and S.M. Bruemmer, Crack-Tip Microstructures and Impurities in Stress-Corrosion-Cracked Alloy 600 from Recirculating and Once-Through Steam Generator, the 10th International Conference on Environmental Degradation of Materials in Nuclear Power Systems Water Reactors, NACE International, Houston, Texas (2001).

6. ASTM E 11296, Standard Test Methods for Determining Average Grain Size, Vol. 03.01, Book of ASTM Standards, ASTM, West Conshohocken, PA (2000).

7. R.S. Pathania, A.R. McIlree, and J. Hickling, Overview of Primary Water Cracking of Alloys 182/82 in PWRs, Fontevraud 5, Proceedings of Contribution of Materials Investigation to the Resolution of Problems Encountered in Pressurized Water Reactors, September 23-27, 2002, SFEN, Paris, France (2002).

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"Effects of Hydrogen Peroxide and Oxygen on Corrosion of Stainless Steel in High Temperatuer Water" by S. Uchida, T. Satoh, Y. Morishima, T. Hirose, T. Miyazawa, N. Kakinuma, Y. Satoh, N. Usui, and Y. WadaQuestions and Answers

"Effect of the Plastic Strain Level Quantified by EBSP Method on the Stress Corrosion Cracking of L-Grade Stainless Steels" by Y. Katayama, M. Tsubota, and Y. SaitoQuestions and Answers

"Correlation Between Deformation-Induced Microstructures and TGSCC Susceptibility in a Low Carbon Austenitic Stainless Steel" by A. Kimura, T. Noda, H. Ohkubo, Y. Kamada, and S. TakahashiQuestions and Answers

"The Initiation of Environmentally Assisted Cracking in BWR High Temperature Water" by S. Wang, Y. Takeda, K. Sakaguchi, and T. ShojiQuestions and Answers

"Stress Corrosion Cracking of Type 316 and 316L Stainless Steels in High Temperature Water" by N. Ishiyama, M. Mayuzumi, Y. Mizutani, and J.-i. TaniQuestions and Answers

"Crack Growth Behaviors of Low Carbon 316 Stainless Steels in 288C Pure Water" by M. Itow, M. Itatani, M. Kikuchi, and N. TanakaQuestions and Answers

"Influence of Heat Treatment, Aging and Neutron Irradiation on the Fracture Toughness and Crack Growth Rate in BWR Environments of Alloy X-750" by A. Jenssen, P. Efsing, and J. SundbergQuestions and Answers

"Effects of Si on SCC of Irradiated and Unirradiated Stainless Steels and Nickel Alloys" by P.L. Andresen, and M.M. MorraQuestions and Answers

"Stress Corrosion Crack Growth Behavior of Cold Worked Austenitic Stainless Steel in High Temperature Water" by M. Tsubota, Y. Katayama, and Y. SaitoQuestions and Answers

"Finite Element Calculation of Crack Propagation in Type 304 Stainless Steel in Diluted Sulphuric Acid Solution Under Stress Corrosion Conditions" by S. Gavrilov, M. Vankeerberghen, and J. DeconinckQuestions and Answers

"The Electrochemistry of Boiling Water Reactors" by H.S. Kim, M. Urquidi-Macdonald, and D. MacdonaldQuestions and Answers

"Modeling and Experimental Studies of Intergranular Corrosion in Austenitic StainlessSteels Used in Light Water Reactor Systems" by R.G. Faulkner, Y. Yin, J. Cintas, and J.M. MontesQuestions and Answers

"Evaluation of the Fracture Research Institute Theoretical Stress Corrosion Cracking Model" by E.D. Eason, R. Pathania, and T. ShojiQuestions and Answers

Crack Growth"The Effect of Hold Time on the Crack Growth Rate of Sensitized Stainless Steel in High Temperature Water" by A. Jenssen, C. Jansson, and J. SundbergQuestions and Answers

"Effects of Positive and Negative dK/da on SCC Growth Rates" by P.L. Andresen, and M.M. MorraQuestions and Answers

"Evaluation of Stress Corrosion Crack Growth Rate Based on Inspection Data on Alloy 600 Tubing" by Y. Garud, B. Woodman, and G. Boyers"High-Resolution Characterizations of Stress-Corrosion Cracks in Austenitic StainlessSteel from Crack Growth Tests in BWR-Simulated Environments" by S.M. Bruemmer, and L.E. ThomasQuestions and Answers

Zircaloy"Characterization of Oxides Formed on Model Zirconium Alloys in 360C Water Using Micro-Beam Synchrotron Radiation" by A. Yilmazbayhan, M. Gomes da Silva, A. Motta, H.-G. Kim, Y.H. Jeong, J.-Y. Park, R. Comstock, B. Lai, and Z. CaiQuestions and Answers

"Effect of Pre-Deposited Magnetite on Deposition of Nickel Oxides on Zr Surface in 573K Pressurized Water" by J.-W. Yeon, Y. Jung, Y.-K. Choi, and W.-H. KimQuestions and Answers

"Effect of Zinc Injection on Crevice Corrosion Resistance of Pre-Filmed Zircaloy-2 Tube Under Heat Transfer Condition" by H. Kawamura, H. Kanbe, R. Morita, and F. Inada"Transient Oxide Film Growth on Zirconium in High Temperature Aqueous Solutions" by Y. Chen, M. Urquidi-Macdonald, and D.D. Macdonald

Irradiation Assisted Stress Corrosion Cracking"The Effect of Oversize Solute Additions on the Irradiation-Assisted Stress Corrosion Cracking Resistance of Austenitic Stainless Steels" by M.J. Hackett, and G.S. WasQuestions and Answers

"Effect of Metallurgical Condition on Irradiation-Assisted Stress Corrosion Cracking of Commercial Stainless Steels" by J.T. Busby, and G.S. WasQuestions and Answers

"Irradiation-Assisted Stress Corrosion Cracking of Heat-Affected Zones of Austenitic Stainless Steel Welds" by R. Stoenescu, M.L. Castao, S. van Dyck, A. Roth, B. van der Schaaf, C. Ohms, and D. GavilletQuestions and Answers

"Irradiation Effects in a Highly Irradiated Cold Worked Stainless Steel Removed from a Commercial PWR" by J. Conermann, R. Shogan, K. Fujimoto, T. Yonezawa, and Y. YamaguchiQuestions and Answers

"Crack Growth Behavior of Irradiated Austenitic Stainless Steel Weld Heat Affected Zone Material in High-Purity Water at 289C" by O.K. Chopra, B. Alexandreanu, E.E. Gruber, and W.J. Shack"Effect of the Accelerated Irradiation and Hydrogen/Helium Gas on IASCC Characteristics for Highly Irradiated Austenitic Stainless Steels" by K. Fujimoto, T. Yonezawa, E. Wachi, Y. Yamaguchi, M. Nakano, R.P. Shogan, J.P. Massoud, and T.R. Mager"Plastic Deformation Behavior of Type 316LN Stainless Steel in Non-Irradiated, Thermallysensitized Condition or in Irradiated Condition During SSRT" by Y. Miwa, T. Tsukada, and S. JitsukawaQuestions and Answers

"Development of Test Techniques for In-Pile SCC Initiation and Growth Tests and the Current Status of In-Pile Testing at JMTR" by H. Ugachi, Y. Kaji, J. Nakano, Y. Matsui, K. Kawamata, T. Tsukada, N. Nagata, K. Dozaki, and H. TakiguchiQuestions and Answers

"Fractographic Observations on a Highly Irradiated AISI 304 Steel after Constant Load Tests in Simulated PWR Water and Argon and after Supplementary Tensile and Impact Tests" by A. Toivonen, U. Ehrnstn, W. Karlsen, P. Aaltonen, J-P. Massoud, and J-M. BoursierQuestions and Answers

"In-Core Crack Growth Rate Studies on Irradiated Austenitic Stainless Steels in BWR And PWR Conditions in the Halden Reactor" by T.M. Karlsen, P. Bennett, and N.W. Hgberg"Irradiation Assisted Stress Corrosion Cracking Susceptibility of Core Component Materials" by K. Chatani, Y. Kitsunai, M. Kodama, S. Suzuki, Y. Tanaka, S. Ooki, S. Tanaka, and T. Nakamura"Influence of the Neutron Spectrum on the Tensile Properties of Irradiated Austenitic Stainless Steels, in Air and in PWR Environment" by J-P. Massoud, M. amboch, P. Brabec, V.K. Shamardin, V.I. Prokhorov, and Ph. Dubuisson"Study on SCC Growth Behavior of BWR Core Shroud" by S. Ooki, Y. Tanaka, K. Takamori, S. Suzuki, S. Tanaka, Y. Saito, T. Nakamura, T. Kato, K. Chatani, and M. Kodama

Irradiation Effects"Influence of Localized Deformation on Irradiation-Assisted Stress Corrosion Cracking of Proton-Irradiated Austenitic Alloys" by Z. Jiao, J.T. Busby, R. Obata, and G.S. Was"Deformation Structure in 316 Stainless Steel Irradiated in a PWR" by K. Fukuya, K. Fujii, and Y. Kitsunai"Irradiation-Induced Microstructure, Swelling and Post-Irradiation Deformation of Stainless Steel 18Cr-10Ni-Ti Irradiated with Chromium Ions to 1-100 Dpa at 300-635C" by O.V. Borodin, V.V. Bryk, A.S. Kalchenko, A.A. Parkhomenko, V.N. Voyevodin, and F.A. Garner"Microstructural Study and in Situ Investigation of Strain Localization in Ions Irradiated Austenitic Stainless Steels" by C. Pokor, J-P. Massoud, P. Pareige, J. Garnier, D. Loisnard, P. Dubuisson, B. Doisneau, and Y. Brchet"Enhancement of Deuterium Retention in Helium or C(+3) Ion Implanted 18Cr10NiTi Stainess Steel" by G.D. Tolstolutskaya, V.V. Ruzhytskiy, I.E. Kopanets, S.A. Karpov, V.V. Bryk, V.N. Voyevodin, and F.A. Garner"Microstructural Evolution in Neutron-Irradiated Stainless Steels: Comparison of LWR and Fast-Reactor Irradiations" by D. Edwards, E. Simonen, S. Bruemmer, and P. Efsing"Dose Rate Effects on Microchemistry and Microstructure Relevant to LWR Components" by E.P. Simonen, D.J. Edwards, and S.M. Bruemmer"Void Swelling of Austenitic Steels Irradiated with Neutrons at Low Temperatures and Very Low Dpa Rates" by F.A. Garner, S.I. Porollo, Yu.V. Konobeev, and O.P. Maksimkin"Response of PWR Baffle-Former Bolt Loading to Swelling, Irradiation Creep and Bolt Replacement as Revealed Using Finite Element Modeling" by E.P. Simonen, F.A. Garner, N.A. Klymyshyn, and M.B. Toloczko

LAS & RPV Steels"Boric Acid Corrosion of Light Water Reactor Pressure Vessel Materials" by J.-H. Park, O.K. Chopra, K. Natesan, W.J. Shack, and W.H. Cullen, Jr.Questions and Answers

"The Effect of Transients on the Crack Growth Behavior of Low Alloy Steels for Pressure Boundary Components Under Light Water Reactor Operating Conditions" by A. Roth, B. Devrient, D. Gmez-Briceo, J. Lapea, M. Ernestov, M. amboch, U. Ehrnstn, J. Fhl, T. Weienberg, H.-P. Seifert, and S. RitterQuestions and Answers

"Mitigation Effect of Hydrogen Water Chemistry on Stress Corrosion and Low-Frequency Corrosion Fatigue Crack Growth in Low-Alloy Steels" by H.-P. Seifert, and S. RitterQuestions and Answers

Nickel-Based Weld Alloys"Examination 0f Stress Corrosion Cracks in Alloy 182 Weld Metal after Exposure to PWR Primary Water" by P. Scott, M. Foucault, B. Brugier, J. Hickling, and A. McilreeQuestions and Answers

"Development of Crack Growth Rate Disposition Curves for Primary Water Stress Corrosion Cracking (PWSCC) of Alloy 82, 182, and 132 Weldments" by G.A. White, N.S. Nordmann, J. Hickling, and C.D. Harrington"Stress Intensity and Temperature Dependence for Crack Growth Rate in Weld Metal Alloy 182 in Primary PWR Environment" by K. Norring, M. Konig, and J. LagerstromQuestions and Answers

"The Effect of Cold Work and Dissolved Hydrogen in the Stress Corrosion Cracking of Alloy 82 and Alloy 182 Weld Metal" by D.J. Paraventi, and W.C. MoshierQuestions and Answers

"Influence of a Cyclic Loading on the Initiation and Propagation of PWSCC in Weld Metal 182" by F. Vaillant, J.-M. Boursier, T. Couvant, C. Amzallag, and J. ChampredondeQuestions and Answers

"Microstructural and Microchemical Characterization of Primary-Side Cracks in an Alloy 600 Nozzle Head Penetration and its Alloy 182 J-Weld from the Davis-Besse Reactor Vessel" by L. Thomas, B.R. Johnson, J.S. Vetrano, and S.M. BruemmerQuestions and Answers

"The Effect of Grain Orientation on the Cracking Behavior of Alloy 182 in PWR Environment" by B. Alexandreanu, O.K. Chopra, and W.J. ShackQuestions and Answers

"SCC Behavior in the Transitiion Region of an Alloy 182-SA 508 Cl.2 Dissimilar Weld Joint Under Simulated BWR-NWC Conditions" by Q. Peng, T. Shoji, S. Ritter, and H.-P. SeifertQuestions and Answers

"Load Path Effects on the Fracture Toughness of Alloy 82H and 52 Welds in Low Temperature Water" by C.M. Brown, and W.J. MillsQuestions and Answers

"Reduction of Toughness Results for Weld Metal 182 in a PWR Primary Water Environment with Varying Dissolved Hydrogen, Lithium Hydroxide and Boric Acid Concentrations" by B.A. Young, A. Mcilree, and P.J. King"Low Temperature Crack Propagation Evaluation in Pressurized Water Reactor Service" by A. Demma, A. Mcilree, and M. HerreraQuestions and Answers

"Establishment of Experimental Conditions for the SCC Growth Rate Test of Alloy 600 and Ni Base Weld Metal in High Temperature Oxygenated Water" by M. Ozawa, Y. Yamamoto, K. Nakata, M. Itow, N. Tanaka, M. Yamamoto, and J. KuniyaQuestions and Answers

"Evaluation of SCC Crack Growth Rate in Alloy 600 and Its Weld Metals in Simulated BWR Environments" by M. Ozawa, Y. Yamamoto, K. Nakata, M. Itow, N. Tanaka, M. Kikuchi, M. Koshiishi, and J. Kuniya"Evaluation of Mechanical and Environmental Parameters Affecting Primary Water Stress Corrosion Cracking of Nickel-Based Alloys" by J. Kwon, Y.-S. Yi, and J.-S. Kim"Fracture Surface Morphology of Stress Corrosion Cracks in Nickel-Base Welds" by W.J. Mills

Noble Metals & SCC Mitigation"BWR SCC Mitigation Experiences with Hydrogen Water Chemistry" by S. HettiarachchiQuestions and Answers

"Effects of Bulk Water Chemistry on ECP Distribution Inside a Crevice" by Y. Wada, K. Ishida, M. Tachibana, and M. AizawaQuestions and Answers

"The Impact of Oxygen and Hydrogen Recombination Efficiency on the Effectiveness of NMCA in Reducing the Corrosion Potential in Boiling Water Reactors" by T.-K. YehQuestions and Answers

"Online NobleChem Mitigation of SCC" by P.L. Andresen, Y.J. Kim, T.P. Diaz, and S. HettiarachchiQuestions and Answers

"Corrosion Mitigation of BWR Structural Materials by the Photoelectric Method with TiO2 Laboratory Experiments of TiO2 Effect on ECP Behavior and Materials Integrity" by M. Okamura, T. Osato, N. Ichikawa, T. Yotsuyanagi, Y. Tsuchiya, K. Takamori, S. Suzuki, and J. SuzukiQuestions and Answers

"Electrochemical Behavior of Oxygen and Hydrogen on ZrO2 Treated Type 304 Stainless Steels in High Temperature Pure Water" by T.-K. Yeh, C.-H. Tsai, and C.-T. Liu"Corrosion Mitigation of BWR Structural Materials by the Photoelectric Method with TiO2 A SCC Mitigation Technique and Its Feasibility Evaluation " by K. Takamori, S. Suzuki, J. Suzuki, Y. Ishii, J. Takagi, N. Ichikawa, and Y. Fukaya

Operational Experience"Flow Accelerated Corrosion and Cracking of Carbon Steel Piping in Primary Water Operating Experience at the Point Lepreau Generating Station" by J.P. Slade, and T.S. GendronQuestions and Answers

"Risk-Reduction Strategies Used to Manage Cracking of Carbon Steel Primary Coolant Piping at the Point Lepreau Generating Station" by J.P. Slade, and T.S. GendronQuestions and Answers

"Recent In-Service Experience with Degradation of Low Alloy Steel Components Due to Localized Corrosion and Environmentally Assisted Cracking in German PWR Plants" by A. Roth, E. Nowak, M. Widera, U. Ilg, U. Wesseling and R. Zimmer"German Experience with Intergranular Cracking in Austenitic Piping in BWRs and Assessment of Parameters Affecting the In-Service IGSCC Behavior Using an Artificial Neural Network" by R. Kilian, H. Hoffmann, U. Ilg, K. Kster, E. Nowak, U. Wesseling, and M. WideraQuestions and Answers

"Root Cause Failure Analysis of Defected J-Groove Welds in Steam Generator Drainage Nozzles" by P. Efsing, B. Forssgren, and R. KilianQuestions and Answers

"Laboratory Investigation of the Stainless Steel Cladding on the Davis-Besse Reactor Vessel Head" by H. Xu, S. Fyfitch, and J.W. HyresQuestions and Answers

"Laboratory Investigation of PWSCC of CRDM Nozzle 3 and Its J-Groove Weld on the Davis-Besse Reactor Vessel Head" by H. Xu, S. Fyfitch, and J.W. Hyres"Laboratory Investigation of the Alloy 600 Bottom Mounted Instrumentation Nozzle Samples and Weld Boat Sample from South Texas Project Unit 1" by H. Xu, S. Fyfitch, J.W. Hyres, F. Cattant, and A. McIlreeQuestions and Answers

"Boric Acid Corrosion Laboratory Investigation of the Davis-Besse Reactor Pressure Vessel Head" by H. Xu, S. Fyfitch, and J.W. HyresQuestions and Answers

"Measurements of Carbon Steel ECP and Critical Deuterium Concentration Under Candu Conditions in the Halden Reactor" by P.J. Bennett, M.A. McGrath, K. Bagli, and M. Dymarski

PWR Primary"The Role of Surface Films in the Stress Corrosion Cracking of Alloy 600 in PWR Primary Water" by T.S. Mintz, and T.M. DevineQuestions and Answers

"Oxidation of Ni Base Alloys in PWR Water: Oxide Layers and Associated Damage to the Base Metal" by P. Combrade, P.M. Scott, M. Foucault,E. Andrieu, and P. Marcus"Alloy Oxidation Studies Related to PWSCC" by F. Scenini, R.C. Newman, R.A. Cottis,and R.J. JackoQuestions and Answers

"Effect of the Chromium Content and Strain on the Corrosion of Nickel Based Alloys in Primary Water of Pressurized Water Reactors" by F. Delabrouille, L. Legras, F. Vaillant, P. Scott, B. Viguier, and E. AndrieuQuestions and Answers

"The Mechanism and Modeling of Intergranular Stress Corrosion Cracking of Nickel-Chromium-Iron Alloys Exposed to High Purity Water" by G.A. Young, W.W. Wilkening, D.S. Morton, E. Richey, and N. LewisQuestions and Answers

"Crack Initiation in Alloy 600 SG Tubing in Elevated pH PWR Primary Water" by R.J. Jacko, and R.E. GoldQuestions and Answers

"Initiation of SCC in Alloy 600 Wrought Materials: A Laboratory and Statistical Evaluation" by J. DaretQuestions and Answers

"SCC Initiation Testing of Nickel-Based Alloys Using In-Situ Monitored Uniaxial Tensile Specimens" by E. Richey, D.S. Morton, and M.K. SchurmanQuestions and Answers

"Cracking of Alloy 600 Nozzles and Welds in PWRs: Review of Cracking Events andRepair Service Experience" by W. Bamford, and J. HallQuestions and Answers

"Verification of an Intraspecimen Method Using a Constant Stress Test of Sensitized Alloy 600" by S.K. Lee, H.S. Choi, C.B. Bahn, J.H. Kim, and I.S. HwangQuestions and Answers

"In Search of the True Temperature and Stress Intensity Factor Dependencies for PWSCC" by D.S. Morton, S.A. Attanasio, E. Richey, and G.A. YoungQuestions and Answers

"Effects of PWR Primary Water Chemistry and Deaerated Water on SCC" by P.L. Andresen, P.W. Emigh, M.M. Morra, and J. HicklingQuestions and Answers

"Crack Growth Rates in Primary Side Materials in Elevated pH PWR Water" by R.J. Jacko, and R.E. GoldQuestions and Answers

"Evaluation of Crack Growth Rate for Alloy 600 Vessel Penetrations in a Primary Water Environment" by Y. Yamamoto, M. Ozawa, K. Nakata, K. Yoshimoto, M. Toyoda, and J. OkudaQuestions and Answers

"SCC Growth Behavior of Austenitic Stainless Steels in PWR Primary Water Conditions" by C. Guerre, O. Raquet, E. Herms, M. Le Calvar, and G. TurluerQuestions and Answers

"Environmentally Assisted Crack Growth of Cold-Worked Type 304 Stainless Steel in PWR Environments" by D. Tice, N. Platts, K. Rigby, J. Stairmand, and H. FairbrotherQuestions and Answers

"SCC of Cold-Worked Austenitic Stainless Steels in PWR Conditions" by O. Raquet, E. Herms, F. Vaillant, T. Couvant, and J.-M. BoursierQuestions and Answers

"Influence of Carbide Precipitation and Rolling Direction on IGSCC Growth Behaviors of Austenitic Stainless Steels in Hydrogenated High Temperature Water" by K. Arioka, T. Yamada, T. Terachi, and G. ChibaQuestions and Answers

"Effect of Strain-Hardening on Stress Corrosion Cracking of AISI 304L Stainless Steel in PWR Primary Environment at 360C" by T. Couvant, L. Legras, F. Vaillant, J.M. Boursier, and Y. RouillonQuestions and Answers

"10(7) Cycle Fatigue Limit of Type 304L SS in Air and PWR Water, at 150C and 300C" by H.D. Solomon, C. Amzallag, A.J. Vallee, and R.E. Delair"Statistical Analysis of the LCF Behavior of Type 304L SS Tested at 150C and 300C in Air and PWR Water" by H.D. Solomon, and C. AmzallagQuestions and Answers

"Comparison of the Fatigue Life of Type 304L SS as Measured in Load and Strain Controlled Tests" by H.D. Solomon, C. Amzallag, R.E. Delair, and A.J. ValleeQuestions and Answers

PWR Secondary"Laboratory Examination of Pulled Mill Annealed Alloy 600 Steam Generator Tube with Free Span Axial ODSCC" by A.R. Vaia, P.J. Prabhu, and J.M. StevensQuestions and Answers

"Quantitative Morphological Characterization of Deposits Formed in the Secondary System of the Comanche Peak Steam Electric Station Using Scanning Electron Microscopy (SEM)" by S. Nasrazadani, H. Namduri, J. Stevens, and R. TheimerQuestions and Answers

"Impurity Source Terms and Behavior in Nuclear Once-Through Steam Generators" by R. ThompsonQuestions and Answers

"Observations and Insights Into Pb-Assisted Stress Corrosion Cracking of Alloy 600 Steam Generator Tubes" by L.E. Thomas, and S.M. BruemmerQuestions and Answers

"Modeling Concentrated Solution Transport and Accumulation in Steam Generator Tube Support Plate Crevices" by A. Baum, and K. EvansQuestions and Answers

"Clues and Issues in the SCC of High Nickel Alloys Associated with Dissolved Lead" by R.W. StaehleQuestions and Answers

"Effect of Lead Contamination on Steam Generator Tube Degradation" by Y.C. LuQuestions and Answers

"The Effect of Lead Ions on the Dissolution and Passivation of Nickel Base Alloys" by H. Radhakrishnan, R. Newman, and A. CarceaQuestions and Answers

"Effects of Pb on SCC of Alloy 600 and Alloy 690 in Prototypical Steam Generator Chemistries" by J. Lumsden, A. Mcilree, R. Eaker, R. Thompson, and S. Slosnerick"Evaluation of Crack Growth Rate for Alloy 600TT SG Tubing in Primary and Faulted Secondary Water Environments" by Y. Yamamoto, M. Ozawa, K. Nakata, T. Tsuruta, M. Sato, and T. OkabeQuestions and Answers

"Stress Corrosion Cracking of Nickel Alloys in Complex (Liquid and Vapor) Environments" by O. de Bouvier, E.-M. Pavageau, F. Vaillant, L. Legras, and F. DelabrouilleQuestions and Answers

"Effect of Water Chemistry on Corrosion Resistance of Alloy 600 SG Tubes Under Acidic Conditions" by S. Fukuchi, K. Koba, H. Anada, and M. KanzakiQuestions and Answers

"SCC Behavior of Model Alloy 600 Containing Minor Element Cerium in a Caustic Solution" by J.S. Kim, Y.-S. Yi, O.-C. Kwon, Y. Lim, and M. JungQuestions and Answers

"A New Technique for Intergranular Crack Formation in Alloy 600 Steam Generator Tubing" by T.H. Lee, I.S. Hwang, H.S. Chung, and J.Y. Park"Erosion-Corrosion of Alloy UNS N04400" by G. Ogundele, A. Lloyd, S. Pagan, and F. Camacho"Assessment of Amine Specific Effects on the Flow Accelerated Corrosion Rate of Carbon and Low Alloy Steels" by J.M. Jevec, P.J. King, C.A. Pearce, K. Fruzzetti, and K. SedmanQuestions and Answers

"Oxidation Behavior of Austenitic Materials Exposed to Secondary Side Water at 282C" by J. Sarver, and P. King"Characterization of Austenitic Materials Exposed to Secondary Side Water at 282C" by S. Ramamurthy, R. Davidson, S. McIntyre, J. Sarver, and P. KingQuestions and Answers

SuperCritical Water-Cooled Reactors"Challenges and Recent Progress in Corrosion and Stress Corosion Cracking of Alloys for Supercritical Water Reactor Core Components" by G.S. Was, and S. TeysseyreQuestions and Answers

"Effect of Proton Irradiation and Grain Boundary Engineering on Stress Corrosion Cracking of Ferritic-Martensitic Alloys in Supercritical Water" by G. Gupta, and G.S. WasQuestions and Answers

"Corrosion of Zirconium-Based Fuel Cladding Alloys in Supercritical Water" by Y.H. Jeong, J.Y. Park, H.G. Kim, J.T. Busby, E. Gartner, M. Atzmon, G.S. Was, R.J. Comstock, Y.S. Chu, M. Gomes da Silva, A. Yilmazbayhan, and A.T. MottaQuestions and Answers

"Corrosion-Resistant Coatings for Use in a Supercritical Water Candu Reactor" by D.A. Guzonas, J.S. Wills, G.A. McRae, S. Sullivan, K. Chu, K. Heaslip, and M. StoneQuestions and Answers

"Corrosion and Stress Corrosion Cracking of Ferritic-Martensitic Alloys in Supercritical Water" by P. Ampornrat, C.B. Bahn, and G.S. WasQuestions and Answers

"Corrosion of Candidate Materials for Supercritical Water-Cooled Reactors" by T.R. Allen, Y. Chen, L. Tan, X. Ren, K. Sridharan,Questions and Answers

"General Corrosion Properties of Titanium Based Alloys for the Fuel Claddings in the Supercritical Water-Cooled Reactor" by J. Kaneda, S. Kasahara, J. Kuniya, K. Moriya, F. Kano, N. Saito, A. Shioiri, T. Shibayama, and H. TakahashiQuestions and Answers

Waste Materials and Mechanical Properties"Dynamic Strain Aging of Ni-Base Alloys Inconel 600 and 690" by H. Hnninen, M. Ivanchenko, Y. Yagodzinskyy, V. Nevdacha, U. Ehrnstn, and P. Aaltonen"Stifling of Crevice Corrosion in Alloy 22" by K.G. Mon, G.M. Gordon, and R.B. Rebak"Materials Degradation Issues in the U.S. High-Level Nuclear Waste Repository" by K.G. Mon, and F. Hua"SCC Initiation and Growth Rate Studies on Titanium Grade 7 and Base Metal, Welded and Aged Alloy 22 in Concentrated Groundwater" by P.L. Andresen, G.M. Catlin, P.W. Emigh, and G.M. Gordon"Dynamic Strain Ageing and EAC of Deformed Nitrogen-Alloyed AISI 316 Stainless Steels" by U. Ehrnstn, M. Ivanchenko, V. Nevdacha, Y. Yagodzinskyy, A. Toivonen, and H. Hnninen

Author IndexSubject IndexTMS Essentials

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/Description > /Namespace [ (Adobe) (Common) (1.0) ] /OtherNamespaces [ > /FormElements false /GenerateStructure false /IncludeBookmarks false /IncludeHyperlinks false /IncludeInteractive false /IncludeLayers false /IncludeProfiles false /MultimediaHandling /UseObjectSettings /Namespace [ (Adobe) (CreativeSuite) (2.0) ] /PDFXOutputIntentProfileSelector /DocumentCMYK /PreserveEditing true /UntaggedCMYKHandling /LeaveUntagged /UntaggedRGBHandling /UseDocumentProfile /UseDocumentBleed false >> ]>> setdistillerparams> setpagedevice

/ColorImageDict > /JPEG2000ColorACSImageDict > /JPEG2000ColorImageDict > /AntiAliasGrayImages false /DownsampleGrayImages true /GrayImageDownsampleType /Bicubic /GrayImageResolution 300 /GrayImageDepth -1 /GrayImageDownsampleThreshold 1.50000 /EncodeGrayImages true /GrayImageFilter /DCTEncode /AutoFilterGrayImages true /GrayImageAutoFilterStrategy /JPEG /GrayACSImageDict > /GrayImageDict > /JPEG2000GrayACSImageDict > /JPEG2000GrayImageDict > /AntiAliasMonoImages false /DownsampleMonoImages true /MonoImageDownsampleType /Bicubic /MonoImageResolution 1200 /MonoImageDepth -1 /MonoImageDownsampleThreshold 1.50000 /EncodeMonoImages true /MonoImageFilter /CCITTFaxEncode /MonoImageDict > /AllowPSXObjects false /PDFX1aCheck false /PDFX3Check false /PDFXCompliantPDFOnly false /PDFXNoTrimBoxError true /PDFXTrimBoxToMediaBoxOffset [ 0.00000 0.00000 0.00000 0.00000 ] /PDFXSetBleedBoxToMediaBox true /PDFXBleedBoxToTrimBoxOffset [ 0.00000 0.00000 0.00000 0.00000 ] /PDFXOutputIntentProfile () /PDFXOutputCondition () /PDFXRegistryName (http://www.color.org) /PDFXTrapped /Unknown

/Description >>> setdistillerparams> setpagedevice

/ColorImageDict > /JPEG2000ColorACSImageDict > /JPEG2000ColorImageDict > /AntiAliasGrayImages false /DownsampleGrayImages true /GrayImageDownsampleType /Bicubic /GrayImageResolution 300 /GrayImageDepth -1 /GrayImageDownsampleThreshold 1.50000 /EncodeGrayImages true /GrayImageFilter /DCTEncode /AutoFilterGrayImages true /GrayImageAutoFilterStrategy /JPEG /GrayACSImageDict > /GrayImageDict > /JPEG2000GrayACSImageDict > /JPEG2000GrayImageDict > /AntiAliasMonoImages false /DownsampleMonoImages true /MonoImageDownsampleType /Bicubic /MonoImageResolution 1200 /MonoImageDepth -1 /MonoImageDownsampleThreshold 1.50000 /EncodeMonoImages true /MonoImageFilter /CCITTFaxEncode /MonoImageDict > /AllowPSXObjects false /PDFX1aCheck false /PDFX3Check false /PDFXCompliantPDFOnly false /PDFXNoTrimBoxError true /PDFXTrimBoxToMediaBoxOffset [ 0.00000 0.00000 0.00000 0.00000 ] /PDFXSetBleedBoxToMediaBox true /PDFXBleedBoxToTrimBoxOffset [ 0.00000 0.00000 0.00000 0.00000 ] /PDFXOutputIntentProfile () /PDFXOutputCondition () /PDFXRegistryName (http://www.color.org) /PDFXTrapped /Unknown

/Description >>> setdistillerparams> setpagedevice

/ColorImageDict > /JPEG2000ColorACSImageDict > /JPEG2000ColorImageDict > /AntiAliasGrayImages false /DownsampleGrayImages true /GrayImageDownsampleType /Bicubic /GrayImageResolution 300 /GrayImageDepth -1 /GrayImageDownsampleThreshold 1.50000 /EncodeGrayImages true /GrayImageFilter /DCTEncode /AutoFilterGrayImages true /GrayImageAutoFilterStrategy /JPEG /GrayACSImageDict > /GrayImageDict > /JPEG2000GrayACSImageDict > /JPEG2000GrayImageDict > /AntiAliasMonoImages false /DownsampleMonoImages true /MonoImageDownsampleType /Bicubic /MonoImageResolution 1200 /MonoImageDepth -1 /MonoImageDownsampleThreshold 1.50000 /EncodeMonoImages true /MonoImageFilter /CCITTFaxEncode /MonoImageDict > /AllowPSXObjects false /PDFX1aCheck false /PDFX3Check false /PDFXCompliantPDFOnly false /PDFXNoTrimBoxError true /PDFXTrimBoxToMediaBoxOffset [ 0.00000 0.00000 0.00000 0.00000 ] /PDFXSetBleedBoxToMediaBox true /PDFXBleedBoxToTrimBoxOffset [ 0.00000 0.00000 0.00000 0.00000 ] /PDFXOutputIntentProfile () /PDFXOutputCondition () /PDFXRegistryName (http://www.color.org) /PDFXTrapped /Unknown

/Description >>> setdistillerparams> setpagedevice

/ColorImageDict > /JPEG2000ColorACSImageDict > /JPEG2000ColorImageDict > /AntiAliasGrayImages false /CropGrayImages true /GrayImageMinResolution 300 /GrayImageMinResolutionPolicy /OK /DownsampleGrayImages true /GrayImageDownsampleType /Bicubic /GrayImageResolution 300 /GrayImageDepth -1 /GrayImageMinDownsampleDepth 2 /GrayImageDownsampleThreshold 1.50000 /EncodeGrayImages true /GrayImageFilter /DCTEncode /AutoFilterGrayImages true /GrayImageAutoFilterStrategy /JPEG /GrayACSImageDict > /GrayImageDict > /JPEG2000GrayACSImageDict > /JPEG2000GrayImageDict > /AntiAliasMonoImages false /CropMonoImages true /MonoImageMinResolution 1200 /MonoImageMinResolutionPolicy /OK /DownsampleMonoImages true /MonoImageDownsampleType /Bicubic /MonoImageResolution 1200 /MonoImageDepth -1 /MonoImageDownsampleThreshold 1.50000 /EncodeMonoImages true /MonoImageFilter /CCITTFaxEncode /MonoImageDict > /AllowPSXObjects false /CheckCompliance [ /None ] /PDFX1aCheck false /PDFX3Check false /PDFXCompliantPDFOnly false /PDFXNoTrimBoxError true /PDFXTrimBoxToMediaBoxOffset [ 0.00000 0.00000 0.00000 0.00000 ] /PDFXSetBleedBoxToMediaBox true /PDFXBleedBoxToTrimBoxOffset [ 0.00000 0.00000 0.00000 0.00000 ] /PDFXOutputIntentProfile () /PDFXOutputConditionIdentifier () /PDFXOutputCondition () /PDFXRegistryName () /PDFXTrapped /False

/Description > /Namespace [ (Adobe) (Common) (1.0) ] /OtherNamespaces [ > /FormElements false /GenerateStructure false /IncludeBookmarks false /IncludeHyperlinks false /IncludeInteractive false /IncludeLayers false /IncludeProfiles false /MultimediaHandling /UseObjectSettings /Namespace [ (Adobe) (CreativeSuite) (2.0) ] /PDFXOutputIntentProfileSelector /DocumentCMYK /PreserveEditing true /UntaggedCMYKHandling /LeaveUntagged /UntaggedRGBHandling /UseDocumentProfile /UseDocumentBleed false >> ]>> setdistillerparams> setpagedevice

/ColorImageDict > /JPEG2000ColorACSImageDict > /JPEG2000ColorImageDict > /AntiAliasGrayImages false /CropGrayImages true /GrayImageMinResolution 300 /GrayImageMinResolutionPolicy /OK /DownsampleGrayImages true /GrayImageDownsampleType /Bicubic /GrayImageResolution 300 /GrayImageDepth -1 /GrayImageMinDownsampleDepth 2 /GrayImageDownsampleThreshold 1.50000 /EncodeGrayImages true /GrayImageFilter /DCTEncode /AutoFilterGrayImages true /GrayImageAutoFilterStrategy /JPEG /GrayACSImageDict > /GrayImageDict > /JPEG2000GrayACSImageDict > /JPEG2000GrayImageDict > /AntiAliasMonoImages false /CropMonoImages true /MonoImageMinResolution 1200 /MonoImageMinResolutionPolicy /OK /DownsampleMonoImages true /MonoImageDownsampleType /Bicubic /MonoImageResolution 1200 /MonoImageDepth -1 /MonoImageDownsampleThreshold 1.50000 /EncodeMonoImages true /MonoImageFilter /CCITTFaxEncode /MonoImageDict > /AllowPSXObjects false /CheckCompliance [ /None ] /PDFX1aCheck false /PDFX3Check false /PDFXCompliantPDFOnly false /PDFXNoTrimBoxError true /PDFXTrimBoxToMediaBoxOffset [ 0.00000 0.00000 0.00000 0.00000 ] /PDFXSetBleedBoxToMediaBox true /PDFXBleedBoxToTrimBoxOffset [ 0.00000 0.00000 0.00000 0.00000 ] /PDFXOutputIntentProfile () /PDFXOutputConditionIdentifier () /PDFXOutputCondition () /PDFXRegistryName () /PDFXTrapped /False

/Description > /Namespace [ (Adobe) (Common) (1.0) ] /OtherNamespaces [ > /FormElements false /GenerateStructure false /IncludeBookmarks false /IncludeHyperlinks false /IncludeInteractive false /IncludeLayers false /IncludeProfiles false /MultimediaHandling /UseObjectSettings /Namespace [ (Adobe) (CreativeSuite) (2.0) ] /PDFXOutputIntentProfileSelector /DocumentCMYK /PreserveEditing true /UntaggedCMYKHandling /LeaveUntagged /UntaggedRGBHandling /UseDocumentProfile /UseDocumentBleed false >> ]>> setdistillerparams> setpagedevice

/ColorImageDict > /JPEG2000ColorACSImageDict > /JPEG2000ColorImageDict > /AntiAliasGrayImages false /CropGrayImages true /GrayImageMinResolution 300 /GrayImageMinResolutionPolicy /OK /DownsampleGrayImages true /GrayImageDownsampleType /Bicubic /GrayImageResolution 300 /GrayImageDepth -1 /GrayImageMinDownsampleDepth 2 /GrayImageDownsampleThreshold 1.50000 /EncodeGrayImages true /GrayImageFilter /DCTEncode /AutoFilterGrayImages true /GrayImageAutoFilterStrategy /JPEG /GrayACSImageDict > /GrayImageDict > /JPEG2000GrayACSImageDict > /JPEG2000GrayImageDict > /AntiAliasMonoImages false /CropMonoImages true /MonoImageMinResolution 1200 /MonoImageMinResolutionPolicy /OK /DownsampleMonoImages true /MonoImageDownsampleType /Bicubic /MonoImageResolution 1200 /MonoImageDepth -1 /MonoImageDownsampleThreshold 1.50000 /EncodeMonoImages true /MonoImageFilter /CCITTFaxEncode /MonoImageDict > /AllowPSXObjects false /CheckCompliance [ /None ] /PDFX1aCheck false /PDFX3Check false /PDFXCompliantPDFOnly false /PDFXNoTrimBoxError true /PDFXTrimBoxToMediaBoxOffset [ 0.00000 0.00000 0.00000 0.00000 ] /PDFXSetBleedBoxToMediaBox true /PDFXBleedBoxToTrimBoxOffset [ 0.00000 0.00000 0.00000 0.00000 ] /PDFXOutputIntentProfile () /PDFXOutputConditionIdentifier () /PDFXOutputCondition () /PDFXRegistryName () /PDFXTrapped /False

/Description > /Namespace [ (Adobe) (Common) (1.0) ] /OtherNamespaces [ > /FormElements false /GenerateStructure false /IncludeBookmarks false /IncludeHyperlinks false /IncludeInteractive false /IncludeLayers false /IncludeProfiles false /MultimediaHandling /UseObjectSettings /Namespace [ (Adobe) (CreativeSuite) (2.0) ] /PDFXOutputIntentProfileSelector /DocumentCMYK /PreserveEditing true /UntaggedCMYKHandling /LeaveUntagged /UntaggedRGBHandling /UseDocumentProfile /UseDocumentBleed false >> ]>> setdistillerparams> setpagedevice